In the transmission of currents at high voltage, and particularly in distribution systems which are underground, numerous splices or connections are necessary. These are conveniently effected using metallic sleeves crimped to bare ends of the cables followed by applying suitable insulation and shielding. A major problem in such splices is the occurrence of corona discharge in air pockets around the splice. Such discharge tends to rapidly deteriorate cable insulation and cause premature failure of the splice.
U.S. Pat. No. 4,241,004 describes an improved high voltage splice body and an economical method for manufacturing it. In the method of the patent insulating compound is injected into a mold in which end caps are spaced on a mandrel between which an electrode is centrally positioned on the mandrel. After the insulating compound is cured and the assembly is taken from the mold, an elastomeric tube is placed over the molded part bridging the end caps. It has been found that this method has three drawbacks. First, the elastomeric tube must be stretched as it is placed into position over the molded part so that it applies pressure to make intimate contact with the insulating compound. With larger diameter splice bodies this pressure produces significant hoop stress in the part making a field installation on a splice more difficult. Second, the inner surface of the mold must be plated to prevent the insulating compound from adhering to it, and it as been found that the pressures at which insulating compound is injected into the mold wears away the protective coating after a period of time. Finally, because the insulating compound is in direct contact with the mold, backrinding (i.e. small tears along the mold parting line) will occur in the insulating compound at lower mold temperatures than those at which it would be desirable to cure the insulating compound to maximize production.